1. Field of the Invention
The present disclosure relates to a fault current limiter which is one of electric power receiving and distributing equipment, and more particularly, to a high-speed fault current detection circuit for the fault current limiter.
2. Description of the Related Art
As a protection device for protecting an electric circuit from a fault current such as an overcurrent or short-circuit current, a fault current limiter (can be abbreviated as “FCL”), which is one of electric power receiving and distributing equipment, is an apparatus for reducing a fault current below an appropriate value within a short period of time to enhance the mechanical/thermal stress prevention of an electric power device and grid reliability when a large fault current occurs in a grid.
For an example of conventional technologies for high-speed fault current detection circuits as such fault current limiters, the following patent literature disclosed by the applicant of the present disclosure is descried below for reference.    (Patent Literature 1) KR10-2014-0055129 A
A high-speed fault current detection circuit in the related art according to the patent document has a configuration in which a detection signal detected through one common secondary current transformer is shared for a fault currents and surge currents. In terms of a current signal received in the high-speed fault current detection circuit, the size of a surge current is significantly larger than that of a fault current, and thus has a big difference therebetween, and when it is detected with a common detection device and amplified with a common amplifier circuit section, the detection accuracy of a fault current having a size smaller than that of a surge current is reduced, thus causing a problem in the reliability of the high-speed fault current detection circuit as a whole.